Fluorescent inspection lamp



June 7, 1949. H, W, mE 2,472,180

FLUORESCENT INSPECTION LAMP FilSdFeb. l, 1946 Patented June 7, 1949 FLUORESCENT INSPECTION LAMP Harry W. Tittle, Akron, Ohio, assignor to The B. F. Goodrich Company, New York, N. Y., a corporation of New York Application February 1, 1946, Serial No. 644,873

4 Claims.

This invention relates to uorescent inspection lamps and is especially useful in providing a lamp adapted to be passed through small openings of a container for examining the inside of the container.

Objects of the invention are to provide an inspection lamp that is explosion proof, permitting its use in the presence of iniammable gases. Other objects are to provide high resistance t breakage; to provide a maximum amount of light free from shadows; to provide resistance to mechanical shock and breakage; to provide insulation against electrical shock; to provide an article of light weight; to provide ease of handling; to provide a high degree of light at low temperatures; to provide a lamp which may be passed through small openings; to provide secure sealing of the connections; to provide centering of the fluorescent element with respect to its protective casing; to provide good pressure at all electrical connections and to facilitate replacement and repair of the fluorescent element and starter.

These and other objects will appear from the following description and the accompanying drawings.

Of the drawings,

Fig. 1 is a central longitudinal section of an inspection lamp constructed in accordance with and embodying the invention, parts being broken away.

Fig. 2 is a cross section thereof taken on line 2-2 of Fig. 1.

` Fig. 3 is a central cross sectional view of one end of the inspection light taken at 90 to the section of Fig. 1.

Referring to the drawings the numeral I3 designates a tube of transparent plastic material having a high resistance to breakage and of a nature adapted to be machined readily. The tube is preferably of polymerized methyl methacrylate or other suitable plastic material having the property of readily conducting light. One end of the tube I0 is provided with a closure member II, also of transparent plastic material such as that of the tube I0. The tube and the closure member are provided with threads I2 whereby they may be removably secured to each other, and a sealing gasket I3 may be provided between the ends of the tubes and a iiange I4 of the closure member. The closure member has a central passage I5 therethrough and this passage is threaded as at I6 to receive a threaded bushing I1 of a cable sealing and strain resistor member i8 through which the iiexible cable I9 extends. 'The cable encloses supply wires 20, 2l which are connected through the usual ballast (not shown) to power lines for supplying electric current. Within the transparent tube a pair of opposed fluorescent socket members 22, 23 are mounted upon discs 24, 25 respectively, of insulating material which engage the inner walls of the tube and center the sockets within the tubes. Between the sockets the fluorescent lighting element 25 of the ordinary construction4 having contact pins 2l, 28 at one end thereof for engaging in the socket 22 and contact pins 29, 30 for engaging in the socket 23 is mounted between the sockets 22 and 23 so as to be concentrically arranged with respect to the transparent tube I0.

A starter socket 3I is mounted on the insulation disk 25 at the opposite side from the socket 23 for receiving the starter 32. For insulating the starter 32 and providing a housing therefor while at the same time spacing the socket 3| from the closure member II, a tube 33 of insulating material such as fiber is provided and is arranged with one end abutting against the closure member II and the other end abutting the starter socket 3i. For further supporting the socket 23 from the closure member I I a rod 40 preferably of Wire has one end fixed in the closure member and the opposite end is bent inwardly as at 4I and is secured to the socket 23. Wires 42, 43 connect the socket 22 to the socket 23 for supplying current to the opposite end of the fluorescent element and these wires extend through the spacing disk 25 and along the fluorescent element between the element and the inner wall of the tube i0.

For holding the socket 22 at the far end of the light in contact with the fluorescent element, for supporting all of the parts within the tube in proper relation to each other, and to seal the far end of the tube I0 against entrance of inammable gasses or vapors, a second closure member 45 is removably secured to the far end of the tube II) and for this purpose the end of the tube and the closure member are provided with cooperating screw threads 46. For sealing the threaded joint a sealing gasket 41 may be provided. For applying centralized pressure to the parts contained within the tube IIJ, the pressure member is preferably formed with a conical nose 48 which engages the disk 24 only at its center. The disk 24 which is preferably of thin compressed ber insulation, is of a resilient nature and the single point engagement of the closure member with the disk provides equalized pressure on the contacts of the luorescent tube which, due to the resilience of the disk 24, prevents any loose electrical contacts.

The invention provides an inspection lamp which is not readily broken, which is sealed against ame and which provides substantially shadowless light in all directions. Replacement of the fluorescent element may be readily accomplished by removal of the closure member |15 whereupon the socket 22 may be readily Withdrawn from the end' off the fluorescent element, the Wires 42 and 43 being-suiciently long to permit such removal Without disconnecting the wires. The iluorescent element may then be removed and replaced through the openend oi the tube IUI. The removable nature of the' closure member Il permits access to the star-ter 32 for replacement.

Variations may be made Without departing from the scope of the invention as it.is dened. by the following claims.

I claim:

1. A fluorescent inspection lamp comprising a tube. of transparent plastic material having threaded ends, afluorescentv lighting element arranged within the tube, a starter mounted within ther tube at one end of the element, a closure member of transparentv plastic material removablythreaded to one-endof the tube and having a. passage therethrough for a iiexble supply cable, saidcable being' sealed Within said passage, a second removable'closuremember of plastic material threaded to the oppositaend of said tube, aspacing tube surrounding said' starter for spacing said element from the flrst said closure member, means at the second said closure member for holding said element, saidstarter, and said spacing tube aganstthefrst saidf closure member, said means comprisingl a: central protuberance of' the secondfsaid: closure member andi a resilientV discmounted'between= said protuberancefand saidv element and resi-liently supporting said element from said closure member; and?y means for sealing said closure membersito'sad tube.

2. A fluorescenti, inspection-l lam-p comprising aY tube of' transparent plastic material. having threaded ends; a fluorescent lighting element eX- tending longitudinally within thetube,l a starter mounted Within the tube at one end of the element, a, threaded closure memberyof transparent plastic material removably/secured to one endl of the tubeand having a passage therethrough for a flexible supply cable, said' cable being sealed within sad'passage, a second*removablythreadedl olosurefmemberof plasticfmaterial'at theopposit'e end of saidtube, a.l spacing.. tube. surrounding and.

housing said starter of a length exceeding said starter for spacing said element from the first said closure member and holding said element against the second said closure member said threaded closure members permitting adjustment to accommodate variation in the length of said element While maintaining said element in place, and means for sealing` said closure members to said tube.

3. A uorescent inspection lamp comprising a tube of transparent plastic material having a bore and internally threaded end portions, a iluorescent lighting element arranged longitudinally of said tube with contact terminals at each end thereof, socket members at opposite ends of said lighting element and engaging said contact terminals, discs of resilient insulating material mounted on said socket members and engaging the said -bore of the tube for centering said lighting element, a starter removably mounted on one of said discs, a threaded closure member'engaging one threaded end of said tube and having a passage therethrough for a flexible supply cable; means for sealing said supply cable in saidxpase sage, a tubular spacer of insulating material between the disc on which. said starter is mounted and said closure member surrounding andlhousf ing said starter, said tubular spacer exceeding the length of said starter-so as to transmit thecolumfnar stress of the assembly, a second threaded closure member engaging the threads at the op.- posite end of said tube, said second closure ment-` ber having a central protuberance for engaging: the center of the disc at the opposite end of the. tube and with said disc resiliently, holdingY said element in contact withsaidsocket members, and: means for sealing said closure members to said tube.

4. A uorescent inspection lamp as defined, byclaim 3 in which said second closure member has a conical face providingsad central protuber-y ance as a relatively small bearing surface.

HARRY W. TIT ILE.,

REFERENCES CITED The followingv references are of recorct in the iie of this patent:

UNITED STATES PATENTS Number Name Date 2,336,750 Roney et al Dec, 14, 1943; 2,347,174 Cross et al Apr. 25, 1944 

